1. Field of the Invention
The invention relates to diphosphites, and more particularly relates to neoalkyl diphosphites.
2. Description of the Related Art
Diphosphites of the formula: ##STR1##
wherein Y is a divalent radical selected from the group consisting of: ##STR2##
R is independently selected from the group consisting of hydrogen, alkyl of 1 to 6 carbon atoms, preferably of 1 to 4 carbon atoms, and halogen, preferably chlorine or bormine; R.sup.1 is independently selected from the group consisting of hydrogen, alkyl of 1 to 12 carbon atoms, preferably from 1 to 6 carbon atoms, R.sup.2 is independently selected from the group consisting of hydrogen, alkyl of 1 to 12 carbon atoms, preferably of 1 to 9 carbon atoms, and halogen, preferably chlorine or bromine; and R.sup.3 is independently selected from the group consisting of alkyl of 1 to 12 carbon atoms, preferably of 1 to 9 carbon atoms, and halogen, preferably chlorine or bromine, see Dever et al. U.S. Pat. No. 3,467,733 which is incorporated herein by reference. Dever et al. teaches that the diphosphites may be obtained by reacting a cyclic phosphorohalidite of the formula: ##STR3##
wherein R is as previously mentioned, and A is halogen, preferably chlorine or bromine, and lists 5-butyl-5-ethyl-2-chloro-1,3,2,-dioxaphosphorinane, with a hydroxy organic compound of the formula: ##STR4##
wherein R.sup.1, R.sup.2, and R.sup.3 are as previously mentioned, and lists 2,2-bis(4-hydroxyphenyl) propane among others. While some of these phosphites find utility as stabilizers for polymers, it is desired to improve their hydrolytic and ultraviolet light stability.
Consequently, the present invention provides a diphosphite exhibiting improved stability.